Author Topic: SPWM hardware  (Read 924 times)

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Offline AchuTopic starter

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SPWM hardware
« on: May 30, 2019, 03:28:07 am »
Hi,

Could any one guide me on how to create a hardware to make spwm alternating on two two outputs for each half cycle.
I indent not to use a micro-controller.(Though using an u-Controller is easy)
 

Online Psi

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Re: SPWM hardware
« Reply #1 on: May 30, 2019, 03:31:36 am »
You need to explain more about what you are after.
What signals are the inputs and what are the outputs?

If not using a micro controller then you are going to need compactors and latches/flipflops
Greek letter 'Psi' (not Pounds per Square Inch)
 

Offline AchuTopic starter

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Re: SPWM hardware
« Reply #2 on: May 30, 2019, 03:37:01 am »
My aim is to create alternating spwm signals corresponding to each half cycle by comparing sine and ramp/triangular wave.I believe it is evident from the picture.
Yes I'm willing to do it the hard way by not using programming.
I might use it to drive an H bridge to make a crude inverter.
 

Offline pwlps

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Re: SPWM hardware
« Reply #3 on: May 30, 2019, 07:23:48 am »
My aim is to create alternating spwm signals corresponding to each half cycle by comparing sine and ramp/triangular wave.I believe it is evident from the picture.
Yes I'm willing to do it the hard way by not using programming.
I might use it to drive an H bridge to make a crude inverter.

It is not evident from the picture because there is an inconsistency: comparing sine and ramp/triangular wave from the top picture would yield a 50% duty cycle near zero voltage (single pulse PWM) but this is not the case for the bottom picture signal where you would you need a multiple-pulse pwm.  Figure 5.4 in the following link shows how to modify your triangular reference.
https://shodhganga.inflibnet.ac.in/bitstream/10603/33606/10/10_chapter5.pdf
« Last Edit: May 30, 2019, 07:28:31 am by pwlps »
 

Offline AchuTopic starter

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Re: SPWM hardware
« Reply #4 on: May 31, 2019, 01:22:56 am »
My sincere apologies.I am a noobie.
But do you understand what I am trying to communicate?
 

Offline Etesla

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Re: SPWM hardware
« Reply #5 on: May 31, 2019, 02:08:22 am »
The way you turn the triangle wave, sin wave combo into a square wave is with a comparator. The best way to get the PWM square wave output, and its complement, is to use another comparator with the inputs flipped. This gives you control of the dead time (important for H bridge circuits).
 


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